black work

noun

1. work for which a person is paid in cash, with the transaction not recorded or reported, so as to avoid paying income tax on the amount earned.
2. blackwork.

Example Sentences

A kind of embroidery known as “black work”, done in black silk on linen, was popular during the same reign.

From Project Gutenberg

In the afternoon, Anne sat in the same room alone, busy over some black work, on which her tears dropped slowly.

From Project Gutenberg